The objectives of this work are to analyze the control mechanisms that govern the assignment of positional information to cells that function in regulating regeneration and duplication events in imaginal wing discs of Drosophila melanogaster; and to search for differences in patterns of protein distribution and synthesis that correlates with those events. The work will have three main thrusts: 1. Experiments will be conducted to determine the temporal and topographic sequences in which lost anlagen are replaced or existing ones duplicated when imaginal wing discs are partitioned. 2. In mutant strains the normal arrangements of wing structures has been modified; since the absence or relocation of positional cues may affect the ability of disc fragments to restore lost anlagen, an exploration of regeneration events in wing discs from mutant strains will be made. 3. The molecular basis of pattern specification will be sought through a search for regional differences in protein synthesis or distribution in wing discs. Should such patterns be discernible, they will be determined in normal and mutant discs, and followed under conditions of epimorphic regulation in the regeneration and duplication of partitioned discs.